[PATCH] drm/amdgpu: Fixup bad vram size on gmc v6 and v7

[Alex Deucher]

On Mon, Apr 22, 2024 at 9:00 AM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 22.04.24 um 14:33 schrieb Qiang Ma:
> > On Mon, 22 Apr 2024 11:40:26 +0200
> > Christian König <christian.koenig at amd.com> wrote:
> >
> >> Am 22.04.24 um 07:26 schrieb Qiang Ma:
> >>> Some boards(like Oland PRO: 0x1002:0x6613) seem to have
> >>> garbage in the upper 16 bits of the vram size register,
> >>> kern log as follows:
> >>>
> >>> [    6.000000] [drm] Detected VRAM RAM=2256537600M, BAR=256M
> >>> [    6.007812] [drm] RAM width 64bits GDDR5
> >>> [    6.031250] [drm] amdgpu: 2256537600M of VRAM memory ready
> >>>
> >>> This is obviously not true, check for this and clamp the size
> >>> properly. Fixes boards reporting bogus amounts of vram,
> >>> kern log as follows:
> >>>
> >>> [    2.789062] [drm] Probable bad vram size: 0x86800800
> >>> [    2.789062] [drm] Detected VRAM RAM=2048M, BAR=256M
> >>> [    2.789062] [drm] RAM width 64bits GDDR5
> >>> [    2.789062] [drm] amdgpu: 2048M of VRAM memory ready
> >> Well we had patches like this one here before and so far we always
> >> rejected them.
> >>
> >> When the mmCONFIG_MEMSIZE register isn't properly initialized then
> >> there is something wrong with your hardware.
> >>
> >> Working around that in the software driver is not going to fly.
> >>
> >> Regards,
> >> Christian.
> >>
> > Hi Christian:
> > I see that two patches for this issue have been merged, and the
> > patches are as follows:
> >
> > 11544d77e397 drm/amdgpu: fixup bad vram size on gmc v8
> > 0ca223b029a2 drm/radeon: fixup bad vram size on SI
>
> Mhm, I remember that we discussed reverting those but it looks like that
> never happened. I need to ask around internally.
>
> Question is do you see any other problems with the board? E.g. incorrect
> connector or harvesting configuration?

I'll need to dig up the past discussion again, but IIRC, the issue was
only seen on some non-x86 platforms.  Maybe something specific to MMIO
on those?

Alex


>
> Regards,
> Christian.
>
> >
> > Qiang Ma
> >
> >>> Signed-off-by: Qiang Ma <maqianga at uniontech.com>
> >>> ---
> >>>    drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c | 11 +++++++++--
> >>>    drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c | 13 ++++++++++---
> >>>    2 files changed, 19 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c
> >>> b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c index
> >>> 23b478639921..3703695f7789 100644 ---
> >>> a/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c +++
> >>> b/drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c @@ -309,8 +309,15 @@ static
> >>> int gmc_v6_0_mc_init(struct amdgpu_device *adev) }
> >>>     adev->gmc.vram_width = numchan * chansize;
> >>>     /* size in MB on si */
> >>> -   adev->gmc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> >>> 1024ULL * 1024ULL;
> >>> -   adev->gmc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> >>> 1024ULL * 1024ULL;
> >>> +   tmp = RREG32(mmCONFIG_MEMSIZE);
> >>> +   /* some boards may have garbage in the upper 16 bits */
> >>> +   if (tmp & 0xffff0000) {
> >>> +           DRM_INFO("Probable bad vram size: 0x%08x\n", tmp);
> >>> +           if (tmp & 0xffff)
> >>> +                   tmp &= 0xffff;
> >>> +   }
> >>> +   adev->gmc.mc_vram_size = tmp * 1024ULL * 1024ULL;
> >>> +   adev->gmc.real_vram_size = adev->gmc.mc_vram_size;
> >>>
> >>>     if (!(adev->flags & AMD_IS_APU)) {
> >>>             r = amdgpu_device_resize_fb_bar(adev);
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c
> >>> b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c index
> >>> 3da7b6a2b00d..1df1fc578ff6 100644 ---
> >>> a/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c +++
> >>> b/drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c @@ -316,10 +316,10 @@
> >>> static void gmc_v7_0_mc_program(struct amdgpu_device *adev) static
> >>> int gmc_v7_0_mc_init(struct amdgpu_device *adev) {
> >>>     int r;
> >>> +   u32 tmp;
> >>>
> >>>     adev->gmc.vram_width =
> >>> amdgpu_atombios_get_vram_width(adev); if (!adev->gmc.vram_width) {
> >>> -           u32 tmp;
> >>>             int chansize, numchan;
> >>>
> >>>             /* Get VRAM informations */
> >>> @@ -363,8 +363,15 @@ static int gmc_v7_0_mc_init(struct
> >>> amdgpu_device *adev) adev->gmc.vram_width = numchan * chansize;
> >>>     }
> >>>     /* size in MB on si */
> >>> -   adev->gmc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> >>> 1024ULL * 1024ULL;
> >>> -   adev->gmc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) *
> >>> 1024ULL * 1024ULL;
> >>> +   tmp = RREG32(mmCONFIG_MEMSIZE);
> >>> +   /* some boards may have garbage in the upper 16 bits */
> >>> +   if (tmp & 0xffff0000) {
> >>> +           DRM_INFO("Probable bad vram size: 0x%08x\n", tmp);
> >>> +           if (tmp & 0xffff)
> >>> +                   tmp &= 0xffff;
> >>> +   }
> >>> +   adev->gmc.mc_vram_size = tmp * 1024ULL * 1024ULL;
> >>> +   adev->gmc.real_vram_size = adev->gmc.mc_vram_size;
> >>>
> >>>     if (!(adev->flags & AMD_IS_APU)) {
> >>>             r = amdgpu_device_resize_fb_bar(adev);
> >>
>